Generate a failure when QUnit.start is passed a non-numeric argument

[gibson042]

Ref #844

When QUnit.start is passed a truthy but non-numeric argument, its test semaphore decrement sets config.current.semaphore to NaN. Such a condition should generate output analogous to the "Called start() while already started…" failure presented when semaphore dips below zero.

[platinumazure]

I'd love to submit a pull request, but I'm not sure what the best way to handle this situation is. I suppose throwing an exception for an invalid value would make sense, but is there a better way?

[leobalter]

@platinumazure

You should probably use QUnit.pushFailure with a message argument. Ref: https://github.com/jquery/qunit/blob/master/src/test.js#L297

[jzaefferer]

@platinumazure is this still something you want to work on?

[platinumazure]

Ack, sorry, I've been busy with a bunch of other things. If anyone wants to jump on this now feel free.

[rdugue]

Hello, I would like to make a pull request if possible. Should config.current.semaphore be set to a specific value in this case?

[gibson042]

Given that it's already a configuration failure, I don't think the value matters much. But I suppose 0 would let us just get on with the rest of the suite.